From: Marc Zyngier <maz@misterjones.org>
To: Borislav Petkov <bp@alien8.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Will Deacon <will@kernel.org>, Rabin Vincent <rabin@rab.in>,
x86-ml <x86@kernel.org>, lkml <linux-kernel@vger.kernel.org>
Subject: Re: [RFC] Add RIP to scripts/decodecode
Date: Tue, 29 Sep 2020 13:40:03 +0100 [thread overview]
Message-ID: <b18c145f7b96cace7cd503de33c08311@misterjones.org> (raw)
In-Reply-To: <20200929113238.GC21110@zn.tnic>
Hi,
[dropping these ARM people I never heard of...]
On 2020-09-29 12:32, Borislav Petkov wrote:
> Hi,
>
> how about we add RIP to decodecode output? See below.
>
> I've added the couple of people to Cc who seem to use this thing. The
> patch is dirty and needs cleaning still but I think it would be cool to
> have the actual addresses in that output so that when you compare with
> objdump output in another window, you can find the code very quickly.
>
> You'd need to supply the rIP from the splat, though, as an env var:
>
> $ RIP=0xffffffff8329a927 ./scripts/decodecode < ~/tmp/syz/gfs2.splat
> [ 477.379104][T23917] Code: 48 83 ec 28 48 89 3c 24 48 89 54 24 08 e8
> c1 b4 4a fe 48 8d bb 00 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89
> fa 48 c1 ea 03 <80> 3c 02 00 0f 85 97 05 00 00 48 8b 9b 00 01 00 00 48
> 85 db 0f 84
> Cleaned: [48 83 ec 28 48 89 3c 24 48 89 54 24 08 e8 c1 b4 4a fe 48 8d
> bb 00 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80>
> 3c 02 00 0f 85 97 05 00 00 48 8b 9b 00 01 00 00 48 85 db 0f 84]
> Marker: 127
> rIP_sub: 42
> adj_vma: 0xffffffff8329a8fd
> All code
> ========
> ffffffff8329a8fd: 48 83 ec 28 sub $0x28,%rsp
> ffffffff8329a901: 48 89 3c 24 mov %rdi,(%rsp)
> ffffffff8329a905: 48 89 54 24 08 mov %rdx,0x8(%rsp)
> ffffffff8329a90a: e8 c1 b4 4a fe callq
> 0xffffffff81745dd0
> ffffffff8329a90f: 48 8d bb 00 01 00 00 lea 0x100(%rbx),%rdi
> ffffffff8329a916: 48 b8 00 00 00 00 00 movabs
> $0xdffffc0000000000,%rax
> ffffffff8329a91d: fc ff df
> ffffffff8329a920: 48 89 fa mov %rdi,%rdx
> ffffffff8329a923: 48 c1 ea 03 shr $0x3,%rdx
> ffffffff8329a927:* 80 3c 02 00 cmpb
> $0x0,(%rdx,%rax,1) <-- trapping instruction
> ffffffff8329a92b: 0f 85 97 05 00 00 jne
> 0xffffffff8329aec8
> ffffffff8329a931: 48 8b 9b 00 01 00 00 mov 0x100(%rbx),%rbx
> ffffffff8329a938: 48 85 db test %rbx,%rbx
> ffffffff8329a93b: 0f .byte 0xf
> ffffffff8329a93c: 84 .byte 0x84
>
> Code starting with the faulting instruction
> ===========================================
> ffffffff8329a8fd: 80 3c 02 00 cmpb
> $0x0,(%rdx,%rax,1)
> ffffffff8329a901: 0f 85 97 05 00 00 jne
> 0xffffffff8329ae9e
> ffffffff8329a907: 48 8b 9b 00 01 00 00 mov 0x100(%rbx),%rbx
> ffffffff8329a90e: 48 85 db test %rbx,%rbx
> ffffffff8329a911: 0f .byte 0xf
> ffffffff8329a912: 84 .byte 0x84
>
Looks neat. Only objection is that RIP is pretty tainted from an
architecture perspective. How about PC instead, which most people
understand immediately?
Bonus points if you can convince decodecode to grok something such
as "do_undefinstr+0x2e0/0x2f0" as the PC! ;-)
Thanks,
M.
--
Who you jivin' with that Cosmik Debris?
next prev parent reply other threads:[~2020-09-29 12:56 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-29 11:32 [RFC] Add RIP to scripts/decodecode Borislav Petkov
2020-09-29 12:40 ` Marc Zyngier [this message]
2020-09-29 13:22 ` Borislav Petkov
2020-09-30 11:14 ` [PATCH] scripts/decodecode: Add the capability to supply the program counter Borislav Petkov
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